Filter



E. 1. SW EETLAND.

FILTER.

APPLICATION man MAR. 30. I9l5.

1,349,238. Patented Aug. 10, 1920.

TIGJ

nu/{ INVENTOR.

WITNESSES W BY fli Qi M 44 51 M ATTORNEY UNITED STATES PATENT OFFICE.

ERNEST J. SWEETLAND, OF MONTCLAIR, NEW JERSEY, ASSIGNOR, BY MESNEASSIGN- MENTS, 1'0 UNITED FILTERS CORPORATION, A CORPORATION OFDELAWARE.

FILTER.

Specification of Letters Patent.

Patented Aug. 10, 1920.

To all whom 'it may concern:

Be it known that I, ERNEST J. SwEn'rLANu,

- a citizen of the United States, residing in My invention re ates ingeneral to filters of the plate and frame type, and has to doparticularly with certain features of construction designed to solveproblems which are most often present in this type of filter, althoughsome bases of my invention are applicable to 'lters of other types. Myinvention is especially useful in connection with a plate and framefilter equipped with metallic filter cloth, and provides a constructionin which such cloth is readily mounted in an efiicient and economicalmanner in a plate and frame filter.

In the accompanying drawings which form a part of this specification,igure 1 is a front elevation of a filter plate con structed inaccordance with my invention, parts of the filter fabric being brokenaway to disclose the internal construction. Fig. 2 is an enlargedfragmentar transverse. sectional view t rough a slight y modifiedconstruction of filter late. F1 3 is a view similar to Fi 1 showing theframe which is adapted to used in a filter of this type.

Referring to the drawings in detail, the numerals 1 and 2 desi nate thetwo longitudinal rods or bars wfiich commonly form a support for filterplates and frames in this well known type of filter construction. Uponthese supports are mounted in alternation the filter plates 3 and frames4, the plates 3 being provided with lugs 5 and 6 engaging, respectively,the supports l and 2, and the frames 4 being provided with similar In 7and 8. Means, not shown,-are provided or clamping the plates and framestightly together in the well known manner in order to secure a ti htjoint between them, as indicated in Fig. I

Each filter plate 3 consists of a substantially rectangular body portlonprovlded with a central section 9 of less thickness than the surroundingflange 10. At the top and bottom of the filter plate, between thecentral portion and the flange, are located the two areas 11 and 12,comprising drainage channels between a plurality of staggel-edprojections 13 and 14, respectively, the surfaces of which are flushwith the surface of the portion 9. Each of the areas 11 com municatcswith the drainage manifold 15 by means of the passage 16, and each ofthe areas 14 communicates with the drainage pet cock 17, through thepassage 18. On each side of the portion 9, and coverin as well the areas11 and 12, is placed a sheet of coarse screen 19, or other suitablereticulated fabric, over which in turn is placed a sheet of filteringmaterial which may be of an suitable character, either cloth or metal.he fabric which I prefer for this purpose is a woven fabric, at leastone set of threads of which is composed of bundles of metallic wires,the fabric preferabl being flattened under pressure, as by ro ling. Sucha fabric dorms an excellent filter medium. I do not claim this fabric asart of m present invention, since it is ully described and claimed in myUnited States Letters Patent No. 1,147,379 granted July 20th 1915. Thedrainage fabric extends beyond the areas 9, 11 and 12, as clearly shownin Figs. 1 and 2, and in the type of device illustrated in thesefigures, is clamped in place by means of a retaining frame or strip 21,which is held in place by means of screws 22 entering the body of theframe. The filter fabric 20 extends beyond the retaining strip 21, and agasket 32 which en gages the edge portions of the filter fabric isretained in position between the stri 21 and'the wall 33 of a recess cutin the lter plate. This asket 32 forms a tight seal between the lterframe and the edges of the filter fabric and prevents seepage of theliquid to be filtered around the edges of the said filter fabric. Thisgasket 32 also projects slightly beyond the face of the filter plate sothat it will engage the filter frame and form a tight joint between thefilter plate and the filter frame. Fig. 2 shows a slight modificationinwhich the screen 19 does not extend completely over the area 11,

the staggered projections 13 extending outwardly into enga ement withthe inner surface of the filter abric 20. A rin gasket 25 surrounds thedrainage manifol 15 and is adapted to form a fluid-ti ht joint againstthe abutting face 26 of t e corresponding filter frame, so that thepassage 27 in the frame, which is adapted to ahne with the passage 15 inthe filter plate, forms a continuous outlet manifold. Similarly,passages 28 in the filter plates alining with passages 29 in the frame.forms a continuous inlet manifold, the joints being sealed in a similarmanner by means of rin gaskets 30. Each filter frame is provide passage31 leading from the passage 29 through the frame into the spacesurrounded b it.

In the operation of the filter above described, the plates and framesare assembled in alternation upon the supports 1 and 2, in the usualmanner, pressure being applied in the usual manner to force the platesand frames tightly together, thus sealing the various joints by means ofthe gaskets already described. The liquid to be filtered is thenintroduced in any suitablemanner into the inlet manifold formedby thepassages 28 and 29. It flows through the various passages 31 into thespace bounded by the filter fabric 20, and the two facing filter plates,and by the filter frame 4 which supports them. It will be understoodthat this liquid is introduced under a suitable pressure. The onlyoutlet for the liquid when thus introduced is through the filter fabric20, by passing through which it is relieved of its solid content. Theclear filtrate thus formed, bein still under pressure, passes up betweentfie interstices of the screen 19, over the area 9, until it reaches thedrainage passage formed by the area 11, and assage 16, leading to theoutlet mani old formed by the alinin passages 15 and 27. It is thendischarged from this outlet manifold in any suitable way. 'The continuedmssage of the sludge, or liquid to be filtered, in this manner resultsin the formation of a cake upon the outer surface of the various sheetsof filter fabric 20. When this cake becomes so thick as to impede thefurther progress of the filtrate through it, the pressure holding theplates and frames together is withdrawn, and the plates and frames maythen be separated for the urpose of removing the cake from the lterfabric. If it is desired, the cake maybe first loosened from the filterfabric by the process known as reversing the flow, that is, shutting offthe supply of slud e or liquid to be filtered and introducing cfiaarwash water into the outlet manifold under pressure so that it will forceits way through the various parts of the filter in a direction which isthe reverse of that in which with a the liquid fiows'in normally passingthrou h the filter. The wash water thus reaches t e inner surface of thevarious sheets of filter fabric 20, and on passing through the fab ricencounters the cake deposited on the outer surface thereof and dislodgesit. After this has been accomplished the fiow of wash water may bedlscontinued, and the residual matter in the filter, and the cakedislodged from the filter plate may be removed by disassembling theparts and frames, as already set forth. The pet cook 17, in connectionwith the passage 18, and area 12, provides a means for draining anysurplus wash water or clear filtrate which may remain in the interior ofthe filter plate after the sup ly of either wash water or liquid to befiltered has been cut off.

It will be obvious that certain features of my invention are useful inother than plate and frame filters, as, for instance, chamber filterpresses. While I have illustrated and described only certain specificembodiments of my invention, I realize that it is susceptible of broadapplication and I do not desire to be limited to the precise structureshown and described.

Having thus described my invention, I claim: 7

1. In a filter of the plate and frame type, a filter plate having thecentral web portion thereof reduced in thickness to provide draina eareas on opposite sides thereof, a filter abric section extending overeach of the drainage areas, a sheet of reticulated spacing materialarranged under each of the filter fabric sections, means upon the platefor positively clamping the edges of the filter fabric sections totheplate, and sealing means also extending around the edges of the filterfabric sections and engaging both the said edges and the plate toprovide a tight joint, said sealing means being carried by the plate andproviding means for sealing the joints between the plate ad'acent filterframes.

2. A filter plate having a drainage area on one side thereof, filterfabric extending over said area, and a peripheral asket engaging theedge portions of the lter fabric and the plate to form a tight jointbetween the members and also arranged to directly engage an adjacentplate to produce a tight joint therewith.

3. In a filter com rising a plurality of separable alined mem iers, afilter plate provided upon one side thereof with a central drainagearea, a section of -filter fabric extending over the draina e area,means carried b the plate for positively securing the filter abrie inposition upon the plate, and

a peripheral gasket extending around the edge portions of the filterfabric and engaging the said edges and the plate to produce a tightjoint, said gasket extending beyond the face of the plate to form ajoint between it and the adjacent member of the filter.

4. A filter plate having the central por- 5 tion thereof reduced inthickness to provide a drainage area,

a filter fabric extending over the drainage area, clamping means carriedby the plate an d engaging edge porplate.

E. J. SWEETLAND.

